On Tue, 26 Oct 2021 08:34:00 -0300 Igor Torrente igormtorrente@gmail.com wrote:

Summary

This series of patches refactor some vkms components in order to introduce new formats to the planes and writeback connector.

Now in the blend function, the plane's pixels are converted to ARGB16161616 and then blended together.

The CRC is calculated based on the ARGB1616161616 buffer. And if required, this buffer is copied/converted to the writeback buffer format.

And to handle the pixel conversion, new functions were added to convert from a specific format to ARGB16161616 (the reciprocal is also true).

Tests

This patch series was tested using the following igt tests: -t ".*kms_plane.*" -t ".*kms_writeback.*" -t ".*kms_cursor_crc*" -t ".*kms_flip.*"

New tests passing

• pipe-A-cursor-size-change
• pipe-A-cursor-alpha-transparent

Performance

Following some optimization proposed by Pekka Paalanen, now the code runs way faster than V1 and slightly faster than the current implementation.

| Frametime | |:---------------:|:---------:|:--------------:|:------------:| | implmentation | Current | Per-pixel(V1) | Per-line(V2) | | frametime range | 8~22 ms | 32~56 ms | 6~19 ms | | Average | 10.0 ms | 35.8 ms | 8.6 ms |

Wow, that's much better than I expected.

What is your benchmark? That is, what program do you use and what operations does it trigger to produce these measurements? What are the sizes of all the planes/buffers involved? What kind of CPU was this ran on?

Thanks, pq

Writeback test

During the development of this patch series, I discovered that the writeback-check-output test wasn't filling the plane correctly.

So, currently, this patch series is failing in this test. But I sent a patch to igt to fix it[1].

XRGB to ARGB behavior

During the development, I decided to always fill the alpha channel of the output pixel whenever the conversion from a format without an alpha channel to ARGB16161616 is necessary. Therefore, I ignore the value received from the XRGB and overwrite the value with 0xFFFF.

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Igor Torrente (8): drm: vkms: Replace the deprecated drm_mode_config_init drm: vkms: Alloc the compose frame using vzalloc drm: vkms: Replace hardcoded value of `vkms_composer.map` to DRM_FORMAT_MAX_PLANES drm: vkms: Add fb information to `vkms_writeback_job` drm: drm_atomic_helper: Add a new helper to deal with the writeback connector validation drm: vkms: Refactor the plane composer to accept new formats drm: vkms: Exposes ARGB_1616161616 and adds XRGB_16161616 formats drm: vkms: Add support to the RGB565 format

drivers/gpu/drm/drm_atomic_helper.c | 47 ++++ drivers/gpu/drm/vkms/vkms_composer.c | 329 +++++++++++++++----------- drivers/gpu/drm/vkms/vkms_drv.c | 6 +- drivers/gpu/drm/vkms/vkms_drv.h | 14 +- drivers/gpu/drm/vkms/vkms_formats.h | 252 ++++++++++++++++++++ drivers/gpu/drm/vkms/vkms_plane.c | 17 +- drivers/gpu/drm/vkms/vkms_writeback.c | 33 ++- include/drm/drm_atomic_helper.h | 3 + 8 files changed, 545 insertions(+), 156 deletions(-) create mode 100644 drivers/gpu/drm/vkms/vkms_formats.h